OverTheWire - Bandit solutions

# Level 0
Here's where you start: http://overthewire.org/wargames/bandit/bandit0.html
The login information is given.
Username: bandit0
Password: bandit0

# Level 1
$ ls
There's a file in your home directory, readme
$ cat readme
The password is in the file
Username: bandit1
Password: boJ9jbbUNNfktd78OOpsqOltutMc3MY1

# Level 2
$ ls
There's a file in your home directory, -
As the cat function treats - as stdin/stdout,
$ cat ./-
where ./ stands for current directly,
it forces cat to treat - as the filename
Username: bandit2
Password: CV1DtqXWVFXTvM2F0k09SHz0YwRINYA9

# Level 3
$ ls
The filename has spaces, spaces in this filename
$ cat "spaces in this filename"
Username: bandit3
Password: UmHadQclWmgdLOKQ3YNgjWxGoRMb5luK

# Level 4
bandit3@bandit:~$ ls
inhere
bandit3@bandit:~$ cd inhere
(returns nothing, probably because it's a hidden file)
bandit3@bandit:~$ ls -a (a for all, including hidden files, those that starts with a .)
.  ..  .hidden
bandit3@bandit:~$ cat .hidden
Username: bandit4
Password: pIwrPrtPN36QITSp3EQaw936yaFoFgAB

# Level 5
bandit4@bandit:~$ ls
inhere
bandit4@bandit:~$ cd inhere
bandit4@bandit:~/inhere$ ls
-file00  -file02  -file04  -file06  -file08
-file01  -file03  -file05  -file07  -file09
(It's said in the website that one of the file is human readable,
so I've decided to cat each file as I don't know how to determine a file's content without doing so)
bandit4@bandit:~/inhere$ cat ./-file00
▒▒▒▒▒▒~%        C[▒걱>▒▒| ▒bandit4@bandit:~/inhere$ cat ./-file01
▒▒▒U"7▒w▒▒▒H▒▒ê▒Q▒▒(▒▒▒#▒▒▒bandit4@bandit:~/inhere$ cat ./-file02
▒T▒v▒▒(▒ִ▒▒▒▒▒A*▒
2J▒Ş؇_▒y7bandit4@bandit:~/inhere$ cat ./-file03
▒.A▒▒u▒▒#▒▒▒w$N?c▒-▒▒Db3▒▒=▒▒bandit4@bandit:~/inhere$ cat ./-file04
▒=<▒W▒▒▒▒▒ht▒Z▒▒!▒▒{▒U
                      ▒bandit4@bandit:~/inhere$ cat ./-file05
+▒▒pm▒▒▒;▒▒:D▒▒^▒▒@▒gl▒Q▒bandit4@bandit:~/inhere$ cat ./-file06
▒▒@▒%@▒▒▒ZP*E▒▒1▒V▒▒▒̫*▒▒▒▒bandit4@bandit:~/inhere$ cat ./-file07
koReBOKuIDDepwhWk7jZC0RTdopnAYKh
Username: bandit5
Password: koReBOKuIDDepwhWk7jZC0RTdopnAYKh